The present invention is directed to a method and to a device for supplying a pressure medium to a deformable hollow body. The hollow body is provided with an opening that receives a supply of the pressure medium.
An arrangement of a hose, which can be used for operating a device for clamping flexible printing plates on a forme cylinder and which can be charged with a pressure medium, is known from EP 0 606 604 B1. The hose is arranged on a fastening strip, fixed in place on the cylinder, in the axial extension approximately in the middle between two axial, prestressed clamping strips that are extending in an axis-parallel groove.
The supply of pressure medium to the hose is accomplished through a connecting tube. The connecting tube extends through the fastening strip and is frictionally connected with a sleeve on the underside of the fastening strip facing away from the hose. The sleeve is sealed with the aid of sealing rings and is connected with a flange arranged on the underside of the fastening strip. The sealing faces between the connecting tube and the sleeve, or between the sleeve and the flange, extend parallel in respect to the pressure and force direction.
The connecting tube, which is embodied as a threaded pin with a bore, projects, on the side facing the hose, through a hole in the casing of the hose into its interior. The connecting tube can be fastened releasably and interlockingly in the interior of the hose by the use of a nut.
When mounting the hose, the hole in the hose casing must be pushed on the connecting tube fixed on the cylinder and, if required, must be fastened on the inside of the hose with a nut. In the arrangement depicted in EP 0 606 604 B1, the mounting of the hose must be performed in the radial direction from the shell surface of the cylinder.
When a pressure medium is supplied to the hose through the connecting tube, the hose inflates or expands and pushes the two clamping strips apart in the circumferential direction of the forme cylinder.
EP 0 307 890 B1 shows a device for clamping and tensioning printing plates on a plate cylinder, by using hoses which can be charged with a pressure medium. For tensioning the printing plate, the entire tensioning and clamping device, which is movably arranged in the cylinder groove, is displaced approximately in the circumferential direction of the plate cylinder. This movement takes place against the force of a restoring spring by use of a hose, which can be charged with a pressure medium and which is supported on the groove wall fixed in the cylinder. The clamping device is operated by a toggle lever, which is maintained in the clamping position by a spring force. A hose is used for opening the clamping device which hose, when charged with a pressure medium, forces the toggle lever out of the extended position against the spring force. The mechanism used for the introduction of a pressure medium into the hose is not explained in this prior art document.
DE 33 09 815 C2 discloses a clamping device for a cylinder shell, wherein a clamping sleeve, together with the shell surface of a journal and O-rings arranged between the journal and the clamping sleeve, form a deformable annular chamber. The supply of a pressure medium takes place through a radial bore through the journal, with an orifice in the annular chamber. When charged with a pressure medium, the clamping sleeve is deformed in the radial direction of the journal and holds a front disk of a cylinder shell.
Additional examples of mechanisms and of devices for holding or clamping of plates or covers on cylinders, and which are operated by pressure media, are provided in the publications EP 0 606 604 A 1, EP 0638 420 A1, EP 0 713 770 B1, EP 0 740 609 B1 or EP 0 858 890 A1, and depict a lever mechanism, the drive mechanism for a toothed rack or leaf spring, a displaceable clamping jaw or the plate or covering for the cylinder itself, which is to be held. The above examples all require an assembly at the end, or laterally inside the channel, of the hose which can be charged with pressure medium in the cylinder.
A solution for supplying a medium charged with pressure to a rotatable body itself is proposed in the publication EP 0 554 815 A1, for example.
The object of the present invention is directed to providing a method and a device for supplying a pressure medium to a deformable hollow body.
In accordance with the present invention, this object is attained by providing the deformable hollow body with a pressure medium receiving opening. The hollow body is arranged on a support surface with its opening aligned with a mouth of a pressure medium supply line. Charging of the hollow body with a pressure medium seals the opening in the hollow body to the supply line and to the support surface. The supply line does not penetrate the hollow body.
The advantages to be realized by the present invention reside, in particular, in that only slight demands are to be made on the accessibility of the supply device for the pressure medium and the position of the hose, since there is no rigid passage, fixed in the cylinder, and extending through the hose wall. The device in accordance with the present invention permits the arrangement of, and exchange of hoses to be supplied with pressure media, at places inside the cylinder, or inside the clamping device, which are difficult to reach. The supply device permits the employment of various types of hoses to be charged with pressure medium for operating holding or clamping devices. For example, the pressure medium hose can be inserted inside the channel into the clamping device in the circumferential direction laterally or at the front or end of the channel.
It is also an advantage of the device of the present invention that, in case of a relative movement between the hose and the line for supplying the pressure medium, no damages occur. This is because the parts of the supply line to be assigned to the cylinder and to the hose do not penetrate each other.
A further advantage of the device of the present invention for supplying pressure medium is the simple and rapid pre-assembly, as well as the insertion into the clamping device, without a requirement for a tool or aids which the invention provides.
The self-sealing property of the device of the present invention, because of the arrangement of the sealing faces perpendicularly to the pressure and force direction acting in the operating state, is particularly advantageous.